I. Technical Field
The present invention relates to a lifting hook device for lifting up a load by suspension on a wire-rope vertically suspended from a winch, such as a crane etc., and furthermore relates to a lifting hook device that lifts so as to constantly maintain a certain direction by avoiding the rotation of the load when especially lifting up the load from an altitude.
II. Description of the Related Art
In general, a lifting hook device is used for mounting and cargo handling in a construction field and a harbor etc. In such a case, the device lifts up the load by hanging a wire-rope on a load and hanging a suspending hook vertically from a winch, such as a crane etc., on the wire-rope. However, when lifting the load, the load rotates on the suspending hook due to the effect of oscillation and wind etc., and it is in danger of hitting surrounding objects and workers. So, previously, various methods and devices have been suggested in order to stop the rotation of the load.
For example, machinery for stopping the rotation of the crane hook in such a way to mechanically-regulate the rotation of a suspending hook is described in Japanese Patent Application Laid-Open No. H07-228468 A, so that the suspending hook is vertically suspended from the housing, i.e., the body freely rotates in case of no-load, and thereby a protrusion mounted in the body is fitted on a hollow by applying the load.
Moreover, a lifting device in such a way to return the lifting device to the prescribed direction, by driving the machine for promoting a circling by a processing signal to estimate and a process that the lifting device circles in any direction by a magnetic azimuth sensor mounted on the lifting device suspended by crane, is described in Japanese Patent Application Laid-Open No. H05-24783 A.